The Independence Party shook up the race for City Hall tonight by unanimously nominating former Bronx President Adolfo Carrion as its standard bearer.

Carrion will face against whoever the Democratic and Republicans elect in their respective party primaries.

“Today the Independence Party gave New Yorkers a real choice. I will not let you down,” Carrion told about 50 of the party’s delegates following their vote at the Scholastic Book Store in Soho.

Carrion, 51, served in the Obama administration as the White House director of urban affairs and later as regional director in the Department of Housing and Urban Development, after his tenure as borough president.

He switched his party affiliation from Democrat to independent last fall.

“The issues are more important than any political party,” Carrion said.

It’s a change of strategy for the Independence Party, who backed Mike Bloomberg in the last three elections. But Bloomberg also ran on the Republican line – and the votes from the two lines combined helped him defeat his three Democratic opponents.

It will be a much more difficult challenge for Carrion to win as a third party candidate – and without Bloomberg’s financial resources . He is also seeking Republican Party support. But because he is not a registered Republican, he needs the backing of three GOP county leaders to run in a Republican primary and that support hasn’t materialized..

But Independence Party political strategist Jacqueline Salit was enthused about Carrion running as a “third force.”

“This is going to be a three way race that’s going to chage the dynamics of politics in New York. Adolfo’s candidacy is defining the race,” Salit said.